Pregnancy & Vitamin D

Date:2008-7-22 12:37

Vitamin D Needs

Vitamin D is a fat soluble vitamin that aids in the absorption of calcium, helping the body produce and maintain strong bones. Only a few foods, like egg yolks, fatty fish and cod liver oil, naturally contain vitamin D. Much of the vitamin D we get comes from fortified foods, such as milk, breakfast cereals, margarine and some brands of orange juice. Another source is sunlight. The skin produces vitamin D when it is exposed to UV-B rays in sunlight. The National Institutes of Health says fifteen minutes of sunlight a few times a week (without sunscreen to block the UV rays) meets the bodies need for vitamin D.

Health experts currently recommend 200 IU (international units) of vitamin D/day for people 50 and under, 400 IU for those 51 to 70 and 600 IU for Americans over 70. An inadequate intake of the vitamin can cause the bones to become thin or brittle. In children, low levels of vitamin D can lead to rickets (a softening and weakening of the bones, which can cause skeletal deformities). In adults, a low “D” intake can cause weak bones and weak muscles (a condition called osteomalacia).

Many people don’t think about how much vitamin D they get each day. But doctors are seeing more cases of vitamin D deficiency in children. Several factors may be involved. Many children spend little time outdoors and those that do often are covered in sunscreen – which blocks the absorption of UV-B rays. Thus children who don’t drink enough milk or eat fortified foods may not be getting enough vitamin D. Breast-fed infants may be at risk because of a low level of vitamin D in breast milk. The American Academy of Pediatrics advises an extra supplement of 200 IU of vitamin D for infants who are exclusively breastfed, bottle fed infants who drink less than 500 mL of vitamin D fortified formula and children and adolescents who don’t get enough of the vitamin in sunlight, fortified milk or supplements.

Vitamin D in Pregnancy

Vitamin D is important for the health of infants, children and adults. But research now shows inadequate intake of vitamin D by a pregnant woman may also have adverse effects on her baby, increasing the risk of low bone mineral density during childhood.

Lisa Bodnar, Ph.D., M.P.H., R.D., Assistant Professor of Epidemiology at the University of Pittsburgh, Graduate School of Public Health, recently examined the vitamin D status of 400 pregnant women in the Pittsburgh area. Half the women were white and half were African-American. Levels of vitamin D were measured from the mom’s blood and from the blood in the umbilical cord (to measure levels in the newborn). More than half of the women who participated in the study were taking a vitamin supplement before pregnancy. 90 percent of the women were taking a vitamin supplement during the last three months of their pregnancy.

Despite the use of supplements, the researchers found a high rate of vitamin D deficiency in the women and their babies. Roughly 45 percent of the white women and 80 percent of the African-American women had low levels of vitamin D. Among the newborns, more than 90 percent of African-American babies and 66 percent of the white babies also had insufficient levels of vitamin D. (Bodnar believes rates of vitamin D deficiency are higher among African-Americans because their dark skin needs longer periods of sunlight exposure to make vitamin D.)

Researchers say that the findings are a wake-up call that pregnant women, even those who have healthy diets and take their prenatal vitamins, may still not be getting enough vitamin D. Bodnar has also found that low levels of vitamin D in breast milk are caused by inadequate intake of the vitamin by the mom. Women who breastfeed should take vitamin D supplements to increase their own levels of the vitamin. The higher levels of “D” will be reflected in the breast milk, providing more of the vitamin to her baby.

Bodnar says the role of vitamin D appears to go way beyond bone health. Almost all the cells in the body have a receptor for vitamin D. A mom’s low “D” intake has been linked to her child’s risk for several other medical conditions, like asthma, type 1 diabetes and schizophrenia. Other research suggests the vitamin may provide some protection for adults against diseases like multiple sclerosis and several types of cancer.

While the researchers focused on the vitamin D levels of pregnant women, Bodnar suggests that Americans of all ages are not getting enough of the vitamin. The current “D” recommendations are based on research completed more than ten years ago. She believes women may need as much as 1,000 IUs of vitamin D or more.